How 'The Leftovers' got that 'famously impossible' Wu-Tang Clan song for the new episode

Van Redin/HBO Warning: Spoilers for the most recent "The Leftovers" below.

If there's one thing the HBO series "The Leftovers" has proven over its brief three-season run, it's that the show loves to shock.

And Sunday's episode was no exception. From the revelation that there might be a way for Nora (Carrie Coon) to see her departed family (the news was delivered to her by none other than the departure-faker and "Perfect Strangers" star Mark Linn-Baker) to that old guy on the tower finally dying, there was a lot to absorb.

But if you're a fan of the legendary hip-hop group Wu-Tang Clan, you were given quite a treat.

When Nora got her cast taken off in the episode, we saw that she has a tattoo of the Wu-Tang "W" symbol on her forearm. We learned when Nora visited Erika (Regina King) that she chose the tattoo to cover previous tattoos of her kids' names.

Erika then revealed to Nora that one way she's kept her sanity after her daughter Eve (Jasmin Savoy Brown) died was buying a trampoline. We then saw the two on the trampoline in slow-motion while the Wu-Tang song "Protect Ya Neck (The Jump Off)" played.

It's just the latest masterful music choice from the show. Though many of the ideas come from the show's cocreator Damon Lindelof and the writers, the person who goes out and clears the song rights is the show's music supervisor Liza Richardson.

When Lindelof first brought up to the idea of the Wu-Tang song to Richardson last February, she wasn't confident. "I said, 'Famously impossible, but let's try,'" Richardson said about getting rights.

Wu-Tang Clan. REUTERS Wu-Tang songs are so hard to clear because they use a lot of samples and there are so many writers for each song.

Lindelof had his eye on a song from the 1995 album "Liquid Swords," a solo album by Wu-Tang member GZA.

Richardson looked into all the songs on the "Liquid Swords" album. It took her close to two months, but she was able to clear the rights to the songs "Liquid Swords" and "Living in the World Today." The track "Shadowboxin'" (featuring Method Man) was also in the running, but there were issues with the samples on the song that held it up.

Richardson was also able to get the rights to "Wu-Tang Clan Ain't Nuthing ta F--- Wit" from their debut album, "Enter the Wu-Tang (36 Chambers)."

Lindelof eventually decided on "Nuthing ta F--- Wit." Or so Richardson thought.

"They changed the scene to Erika and Nora bouncing on the trampoline," she said.

Lindelof now had three new songs he wanted Richardson to go after: "C.R.E.A.M." (from "Enter the Wu-Tang"), "Triumph" ("Wu-Tang Forever"), and "Protect Ya Neck (The Jump Off)" ("The W"). All three cleared and "Protect Ya Neck" was chosen for the scene. The track cost the show $30,000 to use.

Richardson said the music in this episode — from the Wu-Tang track to the episode opening with the "Perfect Strangers" theme song — is a perfect example of why she loves working on the show.

"The variety of music we use is so refreshing," she said. "Like the harp piece at the end of the episode, how often do you get that? In most shows it would be covered with score but we used instrumental music. It's unusual and I think it's killer. This show has been a big left turn for me and I hope I have another chance to do something like this."